logging in or signing up Tracking and positioning of mobile system in telecommunication milus Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 2514 Category: Science & Tech.. License: All Rights Reserved Like it (8) Dislike it (1) Added: October 25, 2010 This Presentation is Public Favorites: 7 Presentation Description No description available. Comments Posting comment... By: monarockss (2 month(s) ago) hey its a nice ppt.. can u mail me at patelmona18@gmail.com.. :) Saving..... Post Reply Close Saving..... Edit Comment Close By: sowmyakharvi (2 month(s) ago) hi.can u mail this ppt to me.my mail id:sowmyakharvi08@gmail.com.thank you... Saving..... 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See all Premium member Presentation Transcript Tracking and positioning of mobile system in telecommunication : Tracking and positioning of mobile system in telecommunication JENNY JOSEPH ROLL:25 Overview : Overview Introduction to mobile technology Need for geolocation Technologies used for geolocation Location tracking curve method Conclusion Configuration of a typical mobile communication : Configuration of a typical mobile communication Description : Description A mobile telecommunication network includes several base stations(T1 to Tn) for providing service to a mobile subscriber through a mobile telephone M1, base station controller (BSC) that controls the base station,and a mobile telephone switching office (MTSO) for connecting the BSC to another BTS or a PSTN(Public switched Telephone network) The whole service area is divided into a several coverage areas having having respective base stations(BS).Each BS coverage area is called a CELL. Each BS is provided with a frequncy ranging between 450 to 900MHz and more than one cell can use the same frequency. Slide 5: An MTSO controls these base stations so that a subscriber can continue his call without interruption while moving between different cells The MTSO can reduce the time required for calling a subscriber by locating the cell of the subscriber Tracking the location of a mobile subscriber within the boundary of the cell in a mobile telecommunication network is known as LOCATION BASED SERVICES Mobile technology includes mainly 2 functions CALL FIXING HANDS OFF PROCESS Need for geolocation : Need for geolocation The ability to obtain the geolocation of the Mobile Telephone in the cellular systems allows the network operators to facilitate new services to the mobile users The geoplocation of the mobile user could provide services like: Emergency service for subscriber safety Billing Cellular fraud detection Intelligent transport systems services Efficient and effective network performance Architecture of geolocation system : Architecture of geolocation system Slide 8: Upon a request from a subscriber about an MS,the service provider will contact a location control centre enquiering the cordinates of the MS. The location control centre gather information required to compute the MS’s location. This informations could be parameters such as received signal strength,TOA of signal etc. Depending upon the past information about the MS’s,a set of BS could be used to page the MS, and directly or indirectly obtain the location parameters Slide 9: Once this information is collected,the location control centre can determine the location of the mobile and convey information to the service provider These are sometimes called geolocation base stations. The service provider use this information to visually display the MS’s location to the subscriber Technologies used for geolocation : Technologies used for geolocation HANDSET BASED MOBILE POSITIOING AND TRACKING global positioning system DIRECTION BASED GEO LOCATION Angle of arrival method DISTANCE BASED POSITIONING Time of arrival method(TOA) Time difference of arrival method(TDOA) Global positioning system(GPS) : Global positioning system(GPS) Slide 12: the A mobile telephone can be located by a mobile telephone itself through a mobile telecommunication network To locate the the mobile telephone by itself, the mobile is provided with a GPS reciever to calculate its location in latitude and longitude cordinates based on the location information received from satellite through receiver. DISADVANTAGES Higher price Increased load High power consumption Angle of arrival method : Angle of arrival method Slide 14: When a mobile user switches the system ON,it receives signal from different BS In this method,it measures the direction of signal falling on the BS and measures the angle of incidence with respect to a normal and determines the position of the system DISADVANTAGES Change in angle of incidence due to any obstacle Inaccurate location when mobile is in between stations Time of arrival method (TOA) : Time of arrival method (TOA) It is assumed that the mobile is located at the intersection point of three circles having radius of the mobile and the BS Distance is calculated by: Ri = C ti = sqrt ( (xi – X ) 2 + (yi – Y) 2 ) where, C – propagation speed of electromagnetic wave, ti – propagation of time from the mobile telephone to ith base station, xi, yi -- location of ith base station, X, Y – mobile position. Time difference of arrival method(TDOA) : Time difference of arrival method(TDOA) Slide 17: Here the mobile is assumed to be located in the overlap area of circles When atleast three circles are overlapped over an area without meeting at one point,the mobile is considered to exist at the intersection point of three common chords This method is still not accurate because it is applicable in case where the mobile is at equal distance from the selected BS Slide 18: When the mobile is not at an equal distance from BS: Location tracking curve method : Location tracking curve method Description : Description Slide 21: This method is used when mobile position cannot be determined by the common chord L1. The two curves TR1 and TR2 have their middle points intersecting the line ST, which connects the positions of the two BSs T1 and T2 and the parts of the two circles C1 and C2 drawn to connect the two intersection points P1 and P2 Instead of the common chord L1,yhe location data processor uses the curve TR1 for the mobile telephone M1 and the curve TR2 for the mobile telephone TR2 Determination of location tracking curve : Determination of location tracking curve Slide 23: If the radio propogation environment between the mobile and the BS is poor due to multi path fading and the NLOS effects,the TOA of the received signal has error. The NLOS has been compared with LOS and the variances of the TOAs of a signal transmitted from the mobile are higher in NLOS By knowing this,appropriate curves can be selected by comparison between the variances of a TOAs of the signal That is,the mobile is nearer from the chord L1 to the one with larger variances out of the two BS That is the mobile neaarer to the BS1 will have a larger variance compared to BS2 Slide 24: Therefore the BS with the smaller variances should be selected to draw reference circle Since the mobile telephone is nearer to BS1 wrt common chord L1,the variances of the TOA’s of a signal transmoitted from the mobile at the first BS T1 will be larger than those of the signal at the BS2 Therfore reference circles TR1 to TR4 are drawn with respect to the BS2 with smaller variances Selecting the centre of the reference circle is significant as the mobile telephone is located on the reference circle. The location data processor selects the desired curves with respect to several BS’s selected for location tracking In figure,as the real location of the mobile telephone deviates farther from the circle C2 with the BS2 at its centre,the centre of the reference circle is farther from the BS2 Reference circle selection : Reference circle selection If the TOAs of the signal at the first BS1 from propagation paths is t1, the first BS1 calculates the variances of t1 The location data processor compares the variances calculated by the BS1 with the variances calculated by BS2 and considers that the mobile telephone is near to that BS with the larger variances. With the larger variances, the center of a reference circle gets farther to the right from the center of BS2. In order to select the desired curve, the location data processor initializes the reference circles with predetermined radii and the variances of TOAs of a signal transmitted located and compare the preset variances with real variance measurements. Slide 26: The location data processor sets a several reference circles based on the distances between the mobile telephone and the BS with the smaller variances , as an example, the first to the fourth reference circles TR1 to TR4 have radii twice, three times, four times, and five times, respectively, of that of BS T2. The variances of the second BS T2 smaller than those of the first BS T1 are used as a criterion for selecting an optimal reference circle. Therefore, the location data processor predetermines the reference variances for the first to the fourth reference circles TR1 to TR4 to be compared with respect to the second BS T1. Slide 27: It is assumed in the following description that 1, 2, and 3 are reference variances and 1< 2< 3 The location data processor selects the base station with smaller variances as a reference point to draw the reference circle. If the selected variances (those of the second BS T2) are , the location data processor compares the selected variances , with the preset reference variances 1, 2, and 3. If <= 1, the curve of the first reference circles TR1 is selected. If 1 < <= 2, the curve of the second reference circles TR2 is selected. If 2 < <= 3, the curve of the third reference circles TR3 is selected. If 3 < , the curve of the fourth reference circles TR4 is selected. Slide 28: , the location data processor selects the optimal curve (reference circle) for the two BSs among the several BSs, and selects another optimal circle for another BS pair, and so on. When curves are selected for all selected BS pairs, the location data processor obtains the intersection points among the selected curves as shown in Figure However, as the selected curves do not intersect at one point due to the multi-path fading or the NLOS effects, the midpoint of these intersection points is determined as the location of the mobile telephone. Slide 30: The location data processor selects a first optimal curve TR1 for BSs T1 and T2, a second optimal curve TR2 for the second and the third BSs, and a third optimal curve TR3 for the first and third BSs. As the three intersection points M1 (xA, yA), M2 (xB, yB), and M3 (xC, yC) are defined by the three curves TR1 to TR3, the location data processor considers the mobile telephone to be located at (x, y). After the location of the mobile telephone, that is, the intersection points among the curves are obtained, the location data processor represents the intersection points in the latitude and the longitude coordinates and transmits the position coordinates to the network (BS/BSC/MSC) and the mobile telephone. Conclusion : Conclusion Our proposal is advantageous in that the location of a mobile telephone can be accurately tracked even in the multi-path fading and the NLOS environment, by using more accurate tracking curves connecting the intersection points among circles with the radii being the distances between corresponding BSs and the mobile telephone in a cellular mobile communication system. We have described about accurate positioning of mobile telephones, which can be used for several applications. The important considerations to be undertaken while selecting a location based technology are location accuracy, implementation cost, reliability, increasing functionality. References : References J. Caffery, and G. Stuber Jr, “Vehicle location and tracking for IVHS in CDMA micro-cells”, Proc. IEEE PIMRC, 1994 G. Morley, and W. Grover, “Improved location estimation with pulse-ranging in presence of shadowing and multi-path excess-delay effects”, Electronics Letters, vol.31, No.18, 1995 www.ieeexplore.ieee.org gp.espacenet.com Slide 33: Thank you You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
Tracking and positioning of mobile system in telecommunication milus Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 2514 Category: Science & Tech.. License: All Rights Reserved Like it (8) Dislike it (1) Added: October 25, 2010 This Presentation is Public Favorites: 7 Presentation Description No description available. Comments Posting comment... By: monarockss (2 month(s) ago) hey its a nice ppt.. can u mail me at patelmona18@gmail.com.. :) Saving..... Post Reply Close Saving..... Edit Comment Close By: sowmyakharvi (2 month(s) ago) hi.can u mail this ppt to me.my mail id:sowmyakharvi08@gmail.com.thank you... Saving..... Post Reply Close Saving..... Edit Comment Close By: sowmyakharvi (2 month(s) ago) hi.can u mail this ppt to me.my mail id:sowmyakharvi08@gmail.com.thank you... Saving..... Post Reply Close Saving..... Edit Comment Close By: sowmyakharvi (2 month(s) ago) hi.can u mail this ppt to me.my mail id:sowmyakharvi08@gmail.com.thank you... Saving..... Post Reply Close Saving..... Edit Comment Close By: sowmyakharvi (2 month(s) ago) hi.can u mail this ppt to me.my mail id:sowmyakharvi08@gmail.com.thank you... Saving..... Post Reply Close Saving..... Edit Comment Close loading.... See all Premium member Presentation Transcript Tracking and positioning of mobile system in telecommunication : Tracking and positioning of mobile system in telecommunication JENNY JOSEPH ROLL:25 Overview : Overview Introduction to mobile technology Need for geolocation Technologies used for geolocation Location tracking curve method Conclusion Configuration of a typical mobile communication : Configuration of a typical mobile communication Description : Description A mobile telecommunication network includes several base stations(T1 to Tn) for providing service to a mobile subscriber through a mobile telephone M1, base station controller (BSC) that controls the base station,and a mobile telephone switching office (MTSO) for connecting the BSC to another BTS or a PSTN(Public switched Telephone network) The whole service area is divided into a several coverage areas having having respective base stations(BS).Each BS coverage area is called a CELL. Each BS is provided with a frequncy ranging between 450 to 900MHz and more than one cell can use the same frequency. Slide 5: An MTSO controls these base stations so that a subscriber can continue his call without interruption while moving between different cells The MTSO can reduce the time required for calling a subscriber by locating the cell of the subscriber Tracking the location of a mobile subscriber within the boundary of the cell in a mobile telecommunication network is known as LOCATION BASED SERVICES Mobile technology includes mainly 2 functions CALL FIXING HANDS OFF PROCESS Need for geolocation : Need for geolocation The ability to obtain the geolocation of the Mobile Telephone in the cellular systems allows the network operators to facilitate new services to the mobile users The geoplocation of the mobile user could provide services like: Emergency service for subscriber safety Billing Cellular fraud detection Intelligent transport systems services Efficient and effective network performance Architecture of geolocation system : Architecture of geolocation system Slide 8: Upon a request from a subscriber about an MS,the service provider will contact a location control centre enquiering the cordinates of the MS. The location control centre gather information required to compute the MS’s location. This informations could be parameters such as received signal strength,TOA of signal etc. Depending upon the past information about the MS’s,a set of BS could be used to page the MS, and directly or indirectly obtain the location parameters Slide 9: Once this information is collected,the location control centre can determine the location of the mobile and convey information to the service provider These are sometimes called geolocation base stations. The service provider use this information to visually display the MS’s location to the subscriber Technologies used for geolocation : Technologies used for geolocation HANDSET BASED MOBILE POSITIOING AND TRACKING global positioning system DIRECTION BASED GEO LOCATION Angle of arrival method DISTANCE BASED POSITIONING Time of arrival method(TOA) Time difference of arrival method(TDOA) Global positioning system(GPS) : Global positioning system(GPS) Slide 12: the A mobile telephone can be located by a mobile telephone itself through a mobile telecommunication network To locate the the mobile telephone by itself, the mobile is provided with a GPS reciever to calculate its location in latitude and longitude cordinates based on the location information received from satellite through receiver. DISADVANTAGES Higher price Increased load High power consumption Angle of arrival method : Angle of arrival method Slide 14: When a mobile user switches the system ON,it receives signal from different BS In this method,it measures the direction of signal falling on the BS and measures the angle of incidence with respect to a normal and determines the position of the system DISADVANTAGES Change in angle of incidence due to any obstacle Inaccurate location when mobile is in between stations Time of arrival method (TOA) : Time of arrival method (TOA) It is assumed that the mobile is located at the intersection point of three circles having radius of the mobile and the BS Distance is calculated by: Ri = C ti = sqrt ( (xi – X ) 2 + (yi – Y) 2 ) where, C – propagation speed of electromagnetic wave, ti – propagation of time from the mobile telephone to ith base station, xi, yi -- location of ith base station, X, Y – mobile position. Time difference of arrival method(TDOA) : Time difference of arrival method(TDOA) Slide 17: Here the mobile is assumed to be located in the overlap area of circles When atleast three circles are overlapped over an area without meeting at one point,the mobile is considered to exist at the intersection point of three common chords This method is still not accurate because it is applicable in case where the mobile is at equal distance from the selected BS Slide 18: When the mobile is not at an equal distance from BS: Location tracking curve method : Location tracking curve method Description : Description Slide 21: This method is used when mobile position cannot be determined by the common chord L1. The two curves TR1 and TR2 have their middle points intersecting the line ST, which connects the positions of the two BSs T1 and T2 and the parts of the two circles C1 and C2 drawn to connect the two intersection points P1 and P2 Instead of the common chord L1,yhe location data processor uses the curve TR1 for the mobile telephone M1 and the curve TR2 for the mobile telephone TR2 Determination of location tracking curve : Determination of location tracking curve Slide 23: If the radio propogation environment between the mobile and the BS is poor due to multi path fading and the NLOS effects,the TOA of the received signal has error. The NLOS has been compared with LOS and the variances of the TOAs of a signal transmitted from the mobile are higher in NLOS By knowing this,appropriate curves can be selected by comparison between the variances of a TOAs of the signal That is,the mobile is nearer from the chord L1 to the one with larger variances out of the two BS That is the mobile neaarer to the BS1 will have a larger variance compared to BS2 Slide 24: Therefore the BS with the smaller variances should be selected to draw reference circle Since the mobile telephone is nearer to BS1 wrt common chord L1,the variances of the TOA’s of a signal transmoitted from the mobile at the first BS T1 will be larger than those of the signal at the BS2 Therfore reference circles TR1 to TR4 are drawn with respect to the BS2 with smaller variances Selecting the centre of the reference circle is significant as the mobile telephone is located on the reference circle. The location data processor selects the desired curves with respect to several BS’s selected for location tracking In figure,as the real location of the mobile telephone deviates farther from the circle C2 with the BS2 at its centre,the centre of the reference circle is farther from the BS2 Reference circle selection : Reference circle selection If the TOAs of the signal at the first BS1 from propagation paths is t1, the first BS1 calculates the variances of t1 The location data processor compares the variances calculated by the BS1 with the variances calculated by BS2 and considers that the mobile telephone is near to that BS with the larger variances. With the larger variances, the center of a reference circle gets farther to the right from the center of BS2. In order to select the desired curve, the location data processor initializes the reference circles with predetermined radii and the variances of TOAs of a signal transmitted located and compare the preset variances with real variance measurements. Slide 26: The location data processor sets a several reference circles based on the distances between the mobile telephone and the BS with the smaller variances , as an example, the first to the fourth reference circles TR1 to TR4 have radii twice, three times, four times, and five times, respectively, of that of BS T2. The variances of the second BS T2 smaller than those of the first BS T1 are used as a criterion for selecting an optimal reference circle. Therefore, the location data processor predetermines the reference variances for the first to the fourth reference circles TR1 to TR4 to be compared with respect to the second BS T1. Slide 27: It is assumed in the following description that 1, 2, and 3 are reference variances and 1< 2< 3 The location data processor selects the base station with smaller variances as a reference point to draw the reference circle. If the selected variances (those of the second BS T2) are , the location data processor compares the selected variances , with the preset reference variances 1, 2, and 3. If <= 1, the curve of the first reference circles TR1 is selected. If 1 < <= 2, the curve of the second reference circles TR2 is selected. If 2 < <= 3, the curve of the third reference circles TR3 is selected. If 3 < , the curve of the fourth reference circles TR4 is selected. Slide 28: , the location data processor selects the optimal curve (reference circle) for the two BSs among the several BSs, and selects another optimal circle for another BS pair, and so on. When curves are selected for all selected BS pairs, the location data processor obtains the intersection points among the selected curves as shown in Figure However, as the selected curves do not intersect at one point due to the multi-path fading or the NLOS effects, the midpoint of these intersection points is determined as the location of the mobile telephone. Slide 30: The location data processor selects a first optimal curve TR1 for BSs T1 and T2, a second optimal curve TR2 for the second and the third BSs, and a third optimal curve TR3 for the first and third BSs. As the three intersection points M1 (xA, yA), M2 (xB, yB), and M3 (xC, yC) are defined by the three curves TR1 to TR3, the location data processor considers the mobile telephone to be located at (x, y). After the location of the mobile telephone, that is, the intersection points among the curves are obtained, the location data processor represents the intersection points in the latitude and the longitude coordinates and transmits the position coordinates to the network (BS/BSC/MSC) and the mobile telephone. Conclusion : Conclusion Our proposal is advantageous in that the location of a mobile telephone can be accurately tracked even in the multi-path fading and the NLOS environment, by using more accurate tracking curves connecting the intersection points among circles with the radii being the distances between corresponding BSs and the mobile telephone in a cellular mobile communication system. We have described about accurate positioning of mobile telephones, which can be used for several applications. The important considerations to be undertaken while selecting a location based technology are location accuracy, implementation cost, reliability, increasing functionality. References : References J. Caffery, and G. Stuber Jr, “Vehicle location and tracking for IVHS in CDMA micro-cells”, Proc. IEEE PIMRC, 1994 G. Morley, and W. Grover, “Improved location estimation with pulse-ranging in presence of shadowing and multi-path excess-delay effects”, Electronics Letters, vol.31, No.18, 1995 www.ieeexplore.ieee.org gp.espacenet.com Slide 33: Thank you